Sewing machines provided with a cloth-edge detector that detects a cloth edge of a workpiece cloth have been conceived. Such sewing machines sew stitches for normal patterns such as straight stitches and zigzag stitches.
An automatically-controlled sewing machine described in JP S62-19193 B (patent document 1) includes a cloth-edge detector, a space-setting circuit, and a swing-width actuator. The cloth-edge detector is provided above a presser foot and outputs a position detection signal by detecting the cloth edge of the workpiece cloth. The space-setting circuit outputs space setting-signals based on spacing from the cloth edge to a stitch-forming baseline (reserved width). The swing-width actuator swings the needle bar based on a position detection signal. Under such configuration, the automatically-controlled sewing machine automatically forms stitches while maintaining consistent spacing from the cloth edge.
On the other hand, there has been conceived an embroidery data generating unit provided with an image reader. The embroidery data generating unit reads a color drawn on an original image by the image reader for each embroidery area, and appends embroidery data with a thread color code of the color read from each embroidery area.
An embroidery data generating unit described in JP H06-142358 A (patent document 2) reads an original image by an image scanner. Then, a color in each embroidery area is read from an image data of the original image, which was read, to determine a thread color of embroidery thread for each embroidery area. Thus, embroidery sewing operation using multiple colors can be executed without having to designate a color in stitch data for each embroidery area if the desired colors are drawn on the original image in advance.
According to the automatically-controlled sewing machine described in patent document 1, stitches can be formed along the cloth edge while maintaining consistent spacing from the cloth edge of the workpiece cloth. However, a pattern selection operation is required upon every instance of switching a stitch pattern to a straight stitch or a zigzag stitch. Also, in sewing two types of zigzag stitches having different needle-swing amount and cloth-feed amount, the user is required to change the settings for the needle-swing amount and the cloth-feed amount during the sewing operation, leading to increased complexity in the sewing work.
Furthermore, the automatically-controlled sewing machine described in patent document 1 is provided with a cloth-edge detector provided above the presser foot in close proximity of a needle drop point, thus providing poor visibility of the needle drop point. Such being the case, it is very difficult to see the actual needle drop point, thereby leading to poor sewing efficiency.
The embroidery data generating unit described in patent document 2 is configured to read the original image having the desired colors drawn thereon in advance by an image scanner to detect the color of each colored embroidery area. However, under such configuration, the type of embroidery stitch to be formed on the embroidery area cannot be changed depending on the detected color. In such case, a method may be employed in which a stitch type such as a satin stitch or a fill stitch is designated by the user upon generation of stitch data for each embroidery area. However such arrangement requires complex editing work on the part of the user.